Feria-Arroyo et al. had reported previously that, based on PCR analysis, 45 % of Ixodes scapulari... more Feria-Arroyo et al. had reported previously that, based on PCR analysis, 45 % of Ixodes scapularis ticks collected in Texas and Mexico were infected with the Lyme disease spirochete Borrelia burgdorferi (Parasit. Vectors 2014, 7:199). However, our analyses of their initial data (Parasit. Vectors 2014, 7:467) and a recent response by Esteve-Gassent et al. (Parasit. Vectors 2015, 8:129) provide evidence that the positive PCR results obtained from both ribosomal RNA intergenic sequences and the flagellin gene flaB are highly likely due to contamination by the B. burgdorferi B31 positive control strain.
The risk of transmission of West Nile virus (WNV) to humans is associated with the density of inf... more The risk of transmission of West Nile virus (WNV) to humans is associated with the density of infected vector mosquitoes in a given area. Current technology for estimating vector distribution and abundance is primarily based on Centers for Disease Control and Prevention (CDC) light trap collections, which provide only point data. In order to estimate mosquito abundance in areas not
We provide a method for constructing a county-level West Nile virus risk map to serve as an early... more We provide a method for constructing a county-level West Nile virus risk map to serve as an early warning system for human cases. We also demonstrate that mosquito surveillance is a more accurate predictor of human risk than monitoring dead and infected wild birds.
Fragmentation of the landscape has been proposed to play an important role in defining local scal... more Fragmentation of the landscape has been proposed to play an important role in defining local scale heterogeneity in Lyme disease risk through influence on mammalian host density and species composition. We tested this observed relationship in a suburban region around Lyme, Connecticut, where we collected data on the density of the tick vector, Ixodes scapularis and prevalence of the Lyme
Arthopods such as Ixodes scapularis ticks serve as vectors for many human pathogens. The arthropo... more Arthopods such as Ixodes scapularis ticks serve as vectors for many human pathogens. The arthropod gut presents a pivotal microbial entry point and determines pathogen colonization and survival. We show that the gut microbiota of I. scapularis, a major vector of the Lyme disease spirochete Borrelia burgdorferi, influence spirochete colonization of ticks. Perturbing the gut microbiota of larval ticks reduced Borrelia colonization, and dysbiosed larvae displayed decreased expression of the transcription factor signal transducer and activator of transcription (STAT). Diminished STAT expression corresponded to lower expression of peritrophin, a key glycoprotein scaffold of the glycan-rich mucus-like peritrophic matrix (PM) that separates the gut lumen from the epithelium. The integrity of the I. scapularis PM was essential for B. burgdorferi to efficiently colonize the gut epithelium. These data elucidate a functional link between the gut microbiota, STAT-signaling, and pathogen coloniz...
In the northeastern United States, the Lyme disease agent, Borrelia burgdorferi sensu stricto, is... more In the northeastern United States, the Lyme disease agent, Borrelia burgdorferi sensu stricto, is maintained by enzoonotic transmission, cycling between white-footed mice (Peromyscus leucopus) and black-legged ticks (Ixodes scapularis). B. burgdorferi sensu stricto is genetically variable and has been divided into three major genotypes based on 16S-23S ribosomal DNA spacer (RST) analysis. To better understand how genetic differ- ences in
The distribution of human risk for West Nile virus was determined by spatial analysis of the init... more The distribution of human risk for West Nile virus was determined by spatial analysis of the initial case distri- bution for the New York City area in 1999 using remote sensing and geographic information system technologies. Cluster analysis revealed the presence of a statistically significant grouping of cases, which also indicates the area of probable virus introduction. Within the cluster,
Lasers and Electro-Optics Society, IEEE LEOS Annual Meeting, 2003
Among the recent emerging flat display technologies organic LED (OLED) is one of the most interes... more Among the recent emerging flat display technologies organic LED (OLED) is one of the most interesting. Combining the OLED with an active matrix substrate, typically made with low temperature polysilicon, it is possible to greatly reduce the power consumption. In an active matrix substrate the ability of integrating active components can be used to mitigate the OLED differential degradation.
Babesia microti and Borrelia burgdorferi, the respective causative agents of human babesiosis and... more Babesia microti and Borrelia burgdorferi, the respective causative agents of human babesiosis and Lyme disease, are maintained in their enzootic cycles by the blacklegged tick (Ixodes scapularis) and use the white-footed mouse (Peromyscus leucopus) as primary reservoir host. The geographic range of both pathogens has expanded in the United States, but the spread of babesiosis has lagged behind that of Lyme disease. Several studies have estimated the basic reproduction number (R0) for B. microti to be below the threshold for persistence (<1), a finding that is inconsistent with the persistence and geographic expansion of this pathogen. We tested the hypothesis that host coinfection with B. burgdorferi increases the likelihood of B. microti transmission and establishment in new areas. We fed I. scapularis larva on P. leucopus mice that had been infected in the laboratory with B. microti and/or B. burgdorferi. We observed that coinfection in mice increases the frequency of B. microt...
Long-term in vitro cultivation of Borrelia miyamotoi, Ticks and Tick-borne Diseases (2014), http:... more Long-term in vitro cultivation of Borrelia miyamotoi, Ticks and Tick-borne Diseases (2014), http://dx.
In order to estimate mosquito abundance in areas not sampled by traps, we developed logistic regr... more In order to estimate mosquito abundance in areas not sampled by traps, we developed logistic regression models for five mosquito species implicated as the most likely vectors of WNV in Connecticut. Using data from 32 traps in Fairfield County from 2001 to 2003, the models were developed to predict high and low abundance for every 30 ؋ 30 m pixel in the County. They were then tested with an independent dataset from 16 traps in adjacent New Haven County. Environmental predictors of abundance were extracted from remotely sensed data. The best predictive models included non-forested areas for Culex pipiens, surface water and distance to estuaries for Cx. salinarius, surface water and grasslands/agriculture for Aedes vexans and seasonal difference in the normalized difference vegetation index and distance to palustrine habitats for Culiseta melanura. No significant predictors were found for Cx. restuans. The sensitivity of the models ranged from 75% to 87.5% and the specificity from 75% to 93.8%. In New Haven County, the models correctly classified 81.3% of the traps for Cx. pipiens, 75.0% for Cx. salinarius, 62.5% for Ae. vexans, and 75.0% for Cs. melanura. Continuous surface maps of habitat suitability were generated for each species for both counties, which could contribute to future surveillance and intervention activities.
This series of articles describes the first large-scale experiment designed to explore the effica... more This series of articles describes the first large-scale experiment designed to explore the efficacy of reducing the risk of tick-borne disease in highly endemic communities of the northeastern and Mid-Atlantic United States through deployment of a self-application device that treats white-tailed deer with acaricide to prevent feeding by adult Ixodes scapularis ticks and all stages of Amblyomma americanum ticks where both species occur. The results of the multicenter study are reported in the accompanying articles in this issue. This article describes the background and rationale for this experiment by reviewing relevant literature on current tick-borne disease epidemics and previous efforts to reduce the public health burden of Lyme disease and other tick-borne diseases.
From 1997 to 2002, the U.S. Department of Agriculture's Northeast Area-wide Tick Control Project ... more From 1997 to 2002, the U.S. Department of Agriculture's Northeast Area-wide Tick Control Project used acaricide-treated 4-Poster Deer Treatment Bait Stations in five eastern states to control ticks feeding on whitetailed deer. The objectives of this host-targeted technology were to reduce free-living blacklegged (Ixodes scapularis Say) and lone star (Amblyomma americanum [L.]) tick populations and thereby to reduce the risk of tickborne disease. During 2002 to 2004, treatments were suspended, and tick population recovery rates were assayed. Subsequently, the major factors that influenced variations in efficacy were extrapolated to better understand and improve this technology. Treatments resulted in significant reductions in free-living populations of nymphal blacklegged ticks at six of the seven sites, and lone star ticks were significantly reduced at all three sites where they were present. During the study, maximal significant ( p 0.05) efficacies against nymphal blacklegged and lone star ticks at individual sites ranged from 60.0 to 81.7 and 90.9 to 99.5%, respectively. The major environmental factor that reduced efficacy was the occurrence of heavy acorn masts, which provided an alternative food resource for deer. Although the 4-Poster technology requires 1 or more years to show efficacy, this host-targeted intervention was demonstrated to be an efficacious, economical, safe, and environment-friendly alternative to area-wide spraying of acaricide to control free-living populations of these tick species.
Proceedings of the National Academy of Sciences, 2004
Many pathogens, such as the agents of West Nile encephalitis and plague, are maintained in nature... more Many pathogens, such as the agents of West Nile encephalitis and plague, are maintained in nature by animal reservoirs and transmitted to humans by arthropod vectors. Efforts to reduce disease incidence usually rely on vector control or immunization of humans. Lyme disease, for which no human vaccine is currently available, is a commonly reported vector-borne disease in North America and Europe. In a recently developed, ecological approach to disease prevention, we intervened in the natural cycle of the Lyme disease agent (Borrelia burgdorferi) by immunizing wild white-footed mice (Peromyscus leucopus), a reservoir host species, with either a recombinant antigen of the pathogen, outer surface protein A, or a negative control antigen in a repeated field experiment with paired experimental and control grids stratified by site. Outer surface protein A vaccination significantly reduced the prevalence of B. burgdorferi in nymphal blacklegged ticks (Ixodes scapularis) collected at the sites the following year in both experiments. The magnitude of the vaccine's effect at a given site correlated with the tick infection prevalence found on the control grid, which in turn correlated with mouse density. These data, as well as differences in the population structures of B. burgdorferi in sympatric ticks and mice, indicated that nonmouse hosts contributed more to infecting ticks than previously expected. Thus, where nonmouse hosts play a large role in infection dynamics, vaccination should be directed at additional species.
Proceedings of the National Academy of Sciences, 2008
North America over the last three decades. To understand the dynamics of the epizootic spread and... more North America over the last three decades. To understand the dynamics of the epizootic spread and to predict the evolutionary trajectories of B. burgdorferi, accurate information on the population structure and the evolutionary relationships of the pathogen is crucial. We, therefore, developed a multilocus sequence typing (MLST) scheme for B. burgdorferi based on eight chromosomal housekeeping genes. We validated the MLST scheme on B. burgdorferi specimens from North America and Europe, comprising both cultured isolates and infected ticks. These data were compared with sequences for the commonly used genetic markers rrs-rrlA intergenic spacer (IGS) and the gene encoding the outer surface protein C (ospC). The study demonstrates that the concatenated sequences of the housekeeping genes of B. burgdorferi provide highly resolved phylogenetic signals and that the housekeeping genes evolve differently compared with the IGS locus and ospC. Using sequence data, the study reveals that North American and European populations of B. burgdorferi correspond to genetically distinct populations. Importantly, the MLST data suggest that B. burgdorferi originated in Europe rather than in North America as proposed previously. evolution ͉ Lyme borreliosis ͉ ticks
Background: Babesia are emerging health threats to humans and animals in the United States. A col... more Background: Babesia are emerging health threats to humans and animals in the United States. A collaborative effort of multiple disciplines to attain optimal health for people, animals and our environment, otherwise known as the One Health concept, was taken during a research workshop held in April 2009 to identify gaps in scientific knowledge regarding babesioses. The impetus for this analysis was the increased risk for outbreaks of bovine babesiosis, also known as Texas cattle fever, associated with the re-infestation of the U.S. by cattle fever ticks.
Vector borne and zoonotic diseases (Larchmont, N.Y.), 2002
The distribution of human risk for West Nile virus was determined by spatial analysis of the init... more The distribution of human risk for West Nile virus was determined by spatial analysis of the initial case distribution for the New York City area in 1999 using remote sensing and geographic information system technologies. Cluster analysis revealed the presence of a statistically significant grouping of cases, which also indicates the area of probable virus introduction. Within the cluster, habitat suitability for potentially infective adult mosquitoes was measured by the amount of vegetation cover using satellite imagery. Logistic regression analysis revealed satellite-derived vegetation abundance to be significantly and positively associated with the presence of human cases. The logistic model was used to estimate the spatial distribution of human risk for West Nile virus throughout New York City. Accuracy of the resulting risk map was cross-validated using virus-positive mosquito sample sites. These new epidemiological methods aid in rapid entry point identification and spatial p...
Feria-Arroyo et al. had reported previously that, based on PCR analysis, 45 % of Ixodes scapulari... more Feria-Arroyo et al. had reported previously that, based on PCR analysis, 45 % of Ixodes scapularis ticks collected in Texas and Mexico were infected with the Lyme disease spirochete Borrelia burgdorferi (Parasit. Vectors 2014, 7:199). However, our analyses of their initial data (Parasit. Vectors 2014, 7:467) and a recent response by Esteve-Gassent et al. (Parasit. Vectors 2015, 8:129) provide evidence that the positive PCR results obtained from both ribosomal RNA intergenic sequences and the flagellin gene flaB are highly likely due to contamination by the B. burgdorferi B31 positive control strain.
The risk of transmission of West Nile virus (WNV) to humans is associated with the density of inf... more The risk of transmission of West Nile virus (WNV) to humans is associated with the density of infected vector mosquitoes in a given area. Current technology for estimating vector distribution and abundance is primarily based on Centers for Disease Control and Prevention (CDC) light trap collections, which provide only point data. In order to estimate mosquito abundance in areas not
We provide a method for constructing a county-level West Nile virus risk map to serve as an early... more We provide a method for constructing a county-level West Nile virus risk map to serve as an early warning system for human cases. We also demonstrate that mosquito surveillance is a more accurate predictor of human risk than monitoring dead and infected wild birds.
Fragmentation of the landscape has been proposed to play an important role in defining local scal... more Fragmentation of the landscape has been proposed to play an important role in defining local scale heterogeneity in Lyme disease risk through influence on mammalian host density and species composition. We tested this observed relationship in a suburban region around Lyme, Connecticut, where we collected data on the density of the tick vector, Ixodes scapularis and prevalence of the Lyme
Arthopods such as Ixodes scapularis ticks serve as vectors for many human pathogens. The arthropo... more Arthopods such as Ixodes scapularis ticks serve as vectors for many human pathogens. The arthropod gut presents a pivotal microbial entry point and determines pathogen colonization and survival. We show that the gut microbiota of I. scapularis, a major vector of the Lyme disease spirochete Borrelia burgdorferi, influence spirochete colonization of ticks. Perturbing the gut microbiota of larval ticks reduced Borrelia colonization, and dysbiosed larvae displayed decreased expression of the transcription factor signal transducer and activator of transcription (STAT). Diminished STAT expression corresponded to lower expression of peritrophin, a key glycoprotein scaffold of the glycan-rich mucus-like peritrophic matrix (PM) that separates the gut lumen from the epithelium. The integrity of the I. scapularis PM was essential for B. burgdorferi to efficiently colonize the gut epithelium. These data elucidate a functional link between the gut microbiota, STAT-signaling, and pathogen coloniz...
In the northeastern United States, the Lyme disease agent, Borrelia burgdorferi sensu stricto, is... more In the northeastern United States, the Lyme disease agent, Borrelia burgdorferi sensu stricto, is maintained by enzoonotic transmission, cycling between white-footed mice (Peromyscus leucopus) and black-legged ticks (Ixodes scapularis). B. burgdorferi sensu stricto is genetically variable and has been divided into three major genotypes based on 16S-23S ribosomal DNA spacer (RST) analysis. To better understand how genetic differ- ences in
The distribution of human risk for West Nile virus was determined by spatial analysis of the init... more The distribution of human risk for West Nile virus was determined by spatial analysis of the initial case distri- bution for the New York City area in 1999 using remote sensing and geographic information system technologies. Cluster analysis revealed the presence of a statistically significant grouping of cases, which also indicates the area of probable virus introduction. Within the cluster,
Lasers and Electro-Optics Society, IEEE LEOS Annual Meeting, 2003
Among the recent emerging flat display technologies organic LED (OLED) is one of the most interes... more Among the recent emerging flat display technologies organic LED (OLED) is one of the most interesting. Combining the OLED with an active matrix substrate, typically made with low temperature polysilicon, it is possible to greatly reduce the power consumption. In an active matrix substrate the ability of integrating active components can be used to mitigate the OLED differential degradation.
Babesia microti and Borrelia burgdorferi, the respective causative agents of human babesiosis and... more Babesia microti and Borrelia burgdorferi, the respective causative agents of human babesiosis and Lyme disease, are maintained in their enzootic cycles by the blacklegged tick (Ixodes scapularis) and use the white-footed mouse (Peromyscus leucopus) as primary reservoir host. The geographic range of both pathogens has expanded in the United States, but the spread of babesiosis has lagged behind that of Lyme disease. Several studies have estimated the basic reproduction number (R0) for B. microti to be below the threshold for persistence (<1), a finding that is inconsistent with the persistence and geographic expansion of this pathogen. We tested the hypothesis that host coinfection with B. burgdorferi increases the likelihood of B. microti transmission and establishment in new areas. We fed I. scapularis larva on P. leucopus mice that had been infected in the laboratory with B. microti and/or B. burgdorferi. We observed that coinfection in mice increases the frequency of B. microt...
Long-term in vitro cultivation of Borrelia miyamotoi, Ticks and Tick-borne Diseases (2014), http:... more Long-term in vitro cultivation of Borrelia miyamotoi, Ticks and Tick-borne Diseases (2014), http://dx.
In order to estimate mosquito abundance in areas not sampled by traps, we developed logistic regr... more In order to estimate mosquito abundance in areas not sampled by traps, we developed logistic regression models for five mosquito species implicated as the most likely vectors of WNV in Connecticut. Using data from 32 traps in Fairfield County from 2001 to 2003, the models were developed to predict high and low abundance for every 30 ؋ 30 m pixel in the County. They were then tested with an independent dataset from 16 traps in adjacent New Haven County. Environmental predictors of abundance were extracted from remotely sensed data. The best predictive models included non-forested areas for Culex pipiens, surface water and distance to estuaries for Cx. salinarius, surface water and grasslands/agriculture for Aedes vexans and seasonal difference in the normalized difference vegetation index and distance to palustrine habitats for Culiseta melanura. No significant predictors were found for Cx. restuans. The sensitivity of the models ranged from 75% to 87.5% and the specificity from 75% to 93.8%. In New Haven County, the models correctly classified 81.3% of the traps for Cx. pipiens, 75.0% for Cx. salinarius, 62.5% for Ae. vexans, and 75.0% for Cs. melanura. Continuous surface maps of habitat suitability were generated for each species for both counties, which could contribute to future surveillance and intervention activities.
This series of articles describes the first large-scale experiment designed to explore the effica... more This series of articles describes the first large-scale experiment designed to explore the efficacy of reducing the risk of tick-borne disease in highly endemic communities of the northeastern and Mid-Atlantic United States through deployment of a self-application device that treats white-tailed deer with acaricide to prevent feeding by adult Ixodes scapularis ticks and all stages of Amblyomma americanum ticks where both species occur. The results of the multicenter study are reported in the accompanying articles in this issue. This article describes the background and rationale for this experiment by reviewing relevant literature on current tick-borne disease epidemics and previous efforts to reduce the public health burden of Lyme disease and other tick-borne diseases.
From 1997 to 2002, the U.S. Department of Agriculture's Northeast Area-wide Tick Control Project ... more From 1997 to 2002, the U.S. Department of Agriculture's Northeast Area-wide Tick Control Project used acaricide-treated 4-Poster Deer Treatment Bait Stations in five eastern states to control ticks feeding on whitetailed deer. The objectives of this host-targeted technology were to reduce free-living blacklegged (Ixodes scapularis Say) and lone star (Amblyomma americanum [L.]) tick populations and thereby to reduce the risk of tickborne disease. During 2002 to 2004, treatments were suspended, and tick population recovery rates were assayed. Subsequently, the major factors that influenced variations in efficacy were extrapolated to better understand and improve this technology. Treatments resulted in significant reductions in free-living populations of nymphal blacklegged ticks at six of the seven sites, and lone star ticks were significantly reduced at all three sites where they were present. During the study, maximal significant ( p 0.05) efficacies against nymphal blacklegged and lone star ticks at individual sites ranged from 60.0 to 81.7 and 90.9 to 99.5%, respectively. The major environmental factor that reduced efficacy was the occurrence of heavy acorn masts, which provided an alternative food resource for deer. Although the 4-Poster technology requires 1 or more years to show efficacy, this host-targeted intervention was demonstrated to be an efficacious, economical, safe, and environment-friendly alternative to area-wide spraying of acaricide to control free-living populations of these tick species.
Proceedings of the National Academy of Sciences, 2004
Many pathogens, such as the agents of West Nile encephalitis and plague, are maintained in nature... more Many pathogens, such as the agents of West Nile encephalitis and plague, are maintained in nature by animal reservoirs and transmitted to humans by arthropod vectors. Efforts to reduce disease incidence usually rely on vector control or immunization of humans. Lyme disease, for which no human vaccine is currently available, is a commonly reported vector-borne disease in North America and Europe. In a recently developed, ecological approach to disease prevention, we intervened in the natural cycle of the Lyme disease agent (Borrelia burgdorferi) by immunizing wild white-footed mice (Peromyscus leucopus), a reservoir host species, with either a recombinant antigen of the pathogen, outer surface protein A, or a negative control antigen in a repeated field experiment with paired experimental and control grids stratified by site. Outer surface protein A vaccination significantly reduced the prevalence of B. burgdorferi in nymphal blacklegged ticks (Ixodes scapularis) collected at the sites the following year in both experiments. The magnitude of the vaccine's effect at a given site correlated with the tick infection prevalence found on the control grid, which in turn correlated with mouse density. These data, as well as differences in the population structures of B. burgdorferi in sympatric ticks and mice, indicated that nonmouse hosts contributed more to infecting ticks than previously expected. Thus, where nonmouse hosts play a large role in infection dynamics, vaccination should be directed at additional species.
Proceedings of the National Academy of Sciences, 2008
North America over the last three decades. To understand the dynamics of the epizootic spread and... more North America over the last three decades. To understand the dynamics of the epizootic spread and to predict the evolutionary trajectories of B. burgdorferi, accurate information on the population structure and the evolutionary relationships of the pathogen is crucial. We, therefore, developed a multilocus sequence typing (MLST) scheme for B. burgdorferi based on eight chromosomal housekeeping genes. We validated the MLST scheme on B. burgdorferi specimens from North America and Europe, comprising both cultured isolates and infected ticks. These data were compared with sequences for the commonly used genetic markers rrs-rrlA intergenic spacer (IGS) and the gene encoding the outer surface protein C (ospC). The study demonstrates that the concatenated sequences of the housekeeping genes of B. burgdorferi provide highly resolved phylogenetic signals and that the housekeeping genes evolve differently compared with the IGS locus and ospC. Using sequence data, the study reveals that North American and European populations of B. burgdorferi correspond to genetically distinct populations. Importantly, the MLST data suggest that B. burgdorferi originated in Europe rather than in North America as proposed previously. evolution ͉ Lyme borreliosis ͉ ticks
Background: Babesia are emerging health threats to humans and animals in the United States. A col... more Background: Babesia are emerging health threats to humans and animals in the United States. A collaborative effort of multiple disciplines to attain optimal health for people, animals and our environment, otherwise known as the One Health concept, was taken during a research workshop held in April 2009 to identify gaps in scientific knowledge regarding babesioses. The impetus for this analysis was the increased risk for outbreaks of bovine babesiosis, also known as Texas cattle fever, associated with the re-infestation of the U.S. by cattle fever ticks.
Vector borne and zoonotic diseases (Larchmont, N.Y.), 2002
The distribution of human risk for West Nile virus was determined by spatial analysis of the init... more The distribution of human risk for West Nile virus was determined by spatial analysis of the initial case distribution for the New York City area in 1999 using remote sensing and geographic information system technologies. Cluster analysis revealed the presence of a statistically significant grouping of cases, which also indicates the area of probable virus introduction. Within the cluster, habitat suitability for potentially infective adult mosquitoes was measured by the amount of vegetation cover using satellite imagery. Logistic regression analysis revealed satellite-derived vegetation abundance to be significantly and positively associated with the presence of human cases. The logistic model was used to estimate the spatial distribution of human risk for West Nile virus throughout New York City. Accuracy of the resulting risk map was cross-validated using virus-positive mosquito sample sites. These new epidemiological methods aid in rapid entry point identification and spatial p...
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